Refrigerated display case



June 2, 1953 H. o. JOHNSON 2,640,330

REFRIGERATED DISPLAY CASE Filed Jan. 5, 1950 2 Sheets-Sheet 1 W0 0. JOHNSON,

INVENTOR.

June 2, 1953 H. o. JOHNSON REFRIGERATED DISPLAY CASE Filed Jan. 5, 1950 2 Sheets-Sheet 2 Hall/Q90 0. JOHNSON,

' INVENTOR.

By I 1 Patented June 2, 1953 umrrso PATENT 2,640 330 REFRIGERATED DISPLAY GASE Howard. lc nl Fer s l-cl A-pplioation January 3, 1950, Serial N 0. 136,633

This invention relates to improvements in open refrigerated display cases.

Several types of open refrigerated display cases which utilize recirculation of air through a cooling. medium and over the open portion or the case to cool articles in the case have heretofore been. used to display articles for sale which must be continually maintained at a relatively low temperature. Such cases have been unsatisfactory for perishable articles such as fruits and vegetables which must not only be maintained at a low temperature, but must also be kept moist. Thus in an open case, the recirculated air is warmed not only by the articles in the case but also by the surrounding air. As the air is thus warmed, its relative humidity is appreciably lowered with the result that the articles over which it passes will be dried out and thereby rendered unsalable. In order to prevent this drying action of the cooling air, it is essential that its relative humidity be maintained at a high value. To impart to the cooling air an initial high humidity several expedients have been employed, each of which has not been satisfactory. For example, the cooling air has been passed through a fine spray. While this scheme successfully imparts to the air the required high initial relative humidity it is expensive to install and to maintain. A second expedient has been to pass the cooling air overice. This scheme requires continual replacement of the ice and is therefore expensive and awkward to lreep in operation. In'addition the problem of imparting to the cooling air a high initial relative humidity it is essential that the air w-hioh contacts the articles in the case does not become too dry during its passage over snch articles. It is therefore necesary that the cooling air be circulated in such a manner that the air which passes in close proximity to the articles in the case be not only cool but also have a high moisture content.

In accordance with the present invention, a simple and inexpensive display case is provided which utilizes the recirculation and r-ecooling of air, and which imparts to the cooling a high relative humidity, and which, by meansof a unique arrangement of bafiies and vents, passes the coolest air in close proximity to the articles in the case and exposes such articles only to air having a relatively high humidity s o as-to prevent excessive drying.

An important object of the inventionis to provide an open refrigerated display case which will maintainarticles the case at a relatively-low ..nuallj ortions of circulating relative humidit o; th smelt ng i s nt hi h.

t is so ano her objec of inventio t provide a c se h ein the articl the ex osed on y to a r her-its a comparaprovide an. open reir .ted. displa is simpl and inexp ns ve to con truct. operate. and main.-

Other objects and advantages of the inyention will become herent upon a rea in o he, lowine desc i ion.

the ec o.., anvins drawin fo min a part o this specificat on. an like numeral are employed t desi nate lik parts throu hout Fi ure 1 is a side showing an open re.- iriserated display case mb dy n my in ention;

Fi ure ,2 a top. view;

figure 3 is. a. sectional view taken along the line 3x3 of; Figure al;

Figure A is a iracment rr s ctional view taken along the line 4 of Figure 3.; and

Figure 5, is a sectional end View of a modification of the invention.

Referring first to Figures 1' through 4 of the drawings wherein-for the purpose of illustration is shown a preferred embodiment of the invention, ..a display case is illustrated having a bottom wall ill, side :walls 14 and i5 and end walls It and Hf As indicated, these Walls are preferably of hollow construction and are filled with a suitable insulating material. Mounted upon the bottom wall l0 is a blower tan l8, associated with a refrigeration coil indicated generallyat 2.0. The coil :20 has an inlet and outlet v(not shown) through which a suitable refrigerant is passed. Inasmuch as many suitable reacadso 22 somewhat wider than the coil 20 and extending longitudinally from behind the fan l8 a substantial portion of the length of the bottom wall H]. An elevated outlet drain 26 is provided in the drip pan to carry off excess water which may collect therein. Due to the elevation of this drain, a level of water is maintained in the drip pan, the purpose of which will be hereinafter described. The elevated outlet drain is preferably removable to facilitate cleaning or flushing of the drip pan.

Spaced inwardly of side walls 44 and are a pair of longitudinally extending inclined side baffles 28. As seen in Figure 2, bafiies 28 extend longitudinally from end wall I! to a position approximately opposite fan [8. These bailies provide a longitudinal air passage along each side wall l4 and I5 which is closed at one end by end wall I! and opens at its other end at a position approximately opposite fan [8. As will hereinafter be described, each such air passage is open along the entire top portion of the bafiie and provides a vent through which the circulating air passes from over the articles in the display case to the blower fan l8. The fan [8 and refrigeration coil are spaced somewhat inwardly of the baffles 28, so asto provide an additional air passage along the inner sides of thesebaflles from the area over the drip pan to the rear of the blower fan l8 and coils 20.

In order to form an air passage between the upper longitudinal edges of each baiiie 28 and its associated side walls l4 and 15 it is necessary to provide suitable spacers. In addition, if relatively light weight material be used for the bafiles 28 it is desirable to provide reinforcing members at points along the lengths of the bafiies. A plurality of bats 32, best seen in Figure 3, are utilized for both these purposes. The bats 33 are spaced I at suitable intervals along the length of each baflie28. w

Two display racks 3B are formed as illustrated in Figure 3, each being angled at 38 parallel with a side baffle 28. A'horizontal flange Mlis utilized to support each display rack upon its associated baflie 28. Vertical glass panes 43 suitably mounted upon side walls I4 and [5 are provided. As

seen, an air passage is provided from above the display racks 36 to-the air passage formed by the side bafiles 2B and the side walls I4 and 15. Optional panes 45 shown in Figure 3 may be attached to the display racks which permit more vegetables or the like to be placed in the rack without clogging the air passage formed between the glass panes 43 and the display racks 36. In

order that excess moisture may run off the display racks and into the drip pan 22, weep holes H3 and drains 12 are provided.

The upper extremities of the display racks 36 are supported by longitudinal members 44, which run the full length of the display racks 3G and are secured to the end walls [6 and I].

As seen in Figure 1, cooling air is forced by the blowing fan l8 over the drip pan 22. The pressure caused by the fan forces a portion of the air upwardly, which air is circulated over the articles in the display racks and eventually returns to the blower fan. For a purpose to be hereinafter described, a header member 48, ex-

tending throughout the length of the display case, is provided. The header 43 as seen in Figure 3 consists of verticalside walls52 each having a number of louvers 54 providing air pas,- sages therein, and a flat bottom wall 56. Bottom wall 55 is preferably inclined upwardly toward 4 each end of the display case as shown in Figure 4.

In the header 48 is inverted channel-shaped deflection plate 58 which is secured to the side walls 52 of the header by a plurality of spacers 66. A tortuous air passage is thus provided from the bottom portion of the display case, through the louvers 54 and through the spacing provided between side walls 52 and deflection plate 58 of the header 48 into the center column 6! Center column Si is provided with screen walls 66 through which the cooling air passes to reach the display rack 38. In order to divert the cooling air downwardly over the display rack a bafile 62 is provided. Screen walls 66 and baffle 62 are mounted on the end walls It and IT in any suitable manner.

The embodiment of the invention above described contains a pair of longitudinal display racks disposed on either side of the center of the case. It is frequently desirable to back an open display case against a wall in which case access can be had to but a single display rack. In Figure 5 is shown a second embodiment of the invention wherein but a single display rack is used. In this embodiment, a single longitudinal side baffle 28 is provided. As seen a blower fan It and refrigeration coil 20 are mounted in the lower portion of the bafiie 28.. While but a single fan and coil combination is shown in Figure 5, if a relatively lon case is used, it is often desirable to use several. Located below the coil 28 is a drip pan 22 which extends longitudinally the full length of the case. Instead of a centrally located header member 48, an inclined bafiie 7B and a'vertical bafiie "58 are provided. Each of these baflies extends longitudinally the full length of the case. Cooling air is forced upwardly through the air passage provided between baffles It and I8, and into the column 30. A screen wall 82 extends the length of the case, providing an air passage from the column 863. A bafile 84 is provided to divert the cooling air through the screen wall 82. The cooling air, after passing over the display rack 36 returns to the blower fan I8 through the air space provided by the spacing between the baffle 23 and the side wall 86.

The operation of the invention is as follows:

Air is drawn in by the fan and cooled by passing over the refrigeration coils. The air then passes over the water filled drip pan 22 absorbing water therefrom. Some of the air then escapes through the louvers 54 into the header 48. The remainder of the air remainswithin the bottom chamber continually absorbing moisture. This remaining portion of air is continually recirculated by the blower fan over the drip pan and back through the refrigeration coils. This air is therefore properly conditioned, that is, given a very low temperature and, due to evaporation from the drip pan, a high humidity. Within a short time after the fan and refrigeration coils are turned on, there is an abundance of cold air with a high moisture content always present in the bottom chamber, due to the construction of the header 48 which enables only a part of the air to escape intothe header.

After the moist air is forced into the header 48 it strikes the deflector plate 58 and is diffused uniformly throughout the header. From there itpasses through the air passage formed by the side walk 52 of the header @8 and the deflector plate 58. This results in substantially a uniform flow of cold moist air along the full length of the header 4B. The cold moist air then passes through the screen Walls {56 andover the display attests? racks 36 maintaining the articles thereon at a suitabie low temperature.

After ov r the di play rack the air flows through the air vents existing between the glass pane 43 and the baffles 8. The air isthen drawn through the air passages existing between the bafiles 2S and the side 'tvails i i and iii to the fan l8. As the coldairis discharged through the refrigeration coil 2i), it mixes with the very moist cold air over the drip pan, and a portion'of this mixture of cold and of very moist air passes upwardly through the header, repeating the cycle. Inasmuch as the cooling air which passes over the display racks is a mixture of cold air from the refrigeration coil and of very moist cold air from the drip pan chamber, the cooling air will have required high relative humidity and low temperature. In addition, inasmuch as the air from the display racl: is passed over the water in the drip pan, most of the dust and foreign particles in the air will settle into the drip pan with the result that the drip pan cleans as well as humidifies the cooling air.

The operation of the embodiment of the invention shown in Figure 5 is essentially the same. Thus the cooling air is circulated upwardly through the passage provided between baffles .46 and 18, through the column 80, through the screen 82 over the display rack 36, and is drawn downwardly through the air passage formed by the bafile 2B and the side wall 86 to the blower fan I 8. The baiiles it and is are so disposed that only a portion of the air in the drip pan chambar is circulated at any one time. The balance of the air remains to be continually circulated through the refrigeration coils and over the drip pan and acquires thereby a high moisture content and a low temperature. A portion of this very cold moist air is continually mixed with a portion of the cold air returned from the display rack to provide a circulating air of relatively high moisture content and of low temperature.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. In an open refrigerated display case, the combination of a display rack, means for cooling and circulating air, a drip pan, a header, means for restricting the flow of air from over said drip pan into said header, an air outlet in said header providing an air passage from said header over the display rack, and a baffie providing an air passage from said display rack to said first mentioned means.

2. In an open refrigerated display case, the combination of a display rack, a blower fan, a cooling coil, a drip pan, a header, a tortuous air passage from over the said drip pan into the said header whereby only a portion of the air over the said drip pan flows into the said header, an air outlet in the said header providing an air passage from said header over said display rack, a baflle disposed above the said header for divert-- ing air out said air outlet, and a second baifie providing an air passage from over said display rack to said blower fan.

3. In a device of the class described, the combination of means for cooling and circulating air, means for humidifying air, a header, louvers provided in said header which will permit a portion disp arraelctes a cir u t me or humidified inn said header. an

e d scribed. the combine area co and ircu a ing a r. drip pen for humid-i ing d spo ed in front .of said air rculatin means. a lensitudinally tending header, louvers provided in said header and so positioned as to permit a portion of humidified air to enter said heater while diverting the remainder of humidified air over said drip pan, an air outlet from said header, a horizontally disposed baiile above said header for deflecting the flow of air from said header air outlet, a display rack disposed in front of said outlet, a vent from said display rack to said air circulating means.

6. In a device of the class described, means for cooling and circulating air, a drip pan, a header disposed above the said drip pan, louvered vertical side walls .for said header providing tortuous air passages from over the said drip pan into the said header, a bailie horizontally disposed between the said sidewalls, a center column above said baffle, a second bafiie horizontally disposed above said center column and acting to divert air outwardly of said center column, a pair of display racks disposed on either side of the said center column and a pair of baffles, one extending from the outward edge of each of the said display racks providing air passages from the said display racks to the air cooling and circulating means.

7. In a device of the class described, an air cooling and circulating means, a drip pan, a header, a vertical baffle, a second inclined baffle, the said bafiles providing a tortuous air passage from over the said drip pan into the said header, a display rack, a horizontal baiile disposed above the said header to divert air over the said display rack and a fourth baiile providing an air passage from over the said display rack to the said air cooling and circulating means.

8. In an open refrigerated display case, the combination of a display rack, a blower fan, a refrigeration coil, a drip pan, a header, a tortuous air passage from over the said drip pan into the header whereby only part of the air over the said drip pan flows into the said header and the remainder of the air is continually recirculated by the blower through the cooling coil and over the drip pan, an air outlet from said header providing an air passage to the display rack, a bafile disposed above said header for diverting air out of said air outlet, and a second bafile providing an air passage over the display rack to said blower fan.

9. In a device of the class described, the combination of a blower fan and refrigeration coil for cooling and circulating air, means for humidifying the air so cooled, a header, louvers provided in the said header to permit a portion of the cooled and humidified air into said header while the remainder of the air is continually recirculated through the refrigeration coil and over the said humidifying means, an air outlet from said header, a display rack, a vent, said louvers, noutlet and vent providing an air passage from 7, over said humidifying means to said blower fan and refrigeration coil.

10. An open refrigerated display case comprising end walls, a bottom wall and side walls, a

blower fan and refrigeration coil for cooling and a circulating air, a drip pan, a header, a tortuous air passage from over said drip pan into said header whereby a portion only of the cooled and humidified air is passed into the said header while the remainder of cooled and humidified air is continually recirculated through the said refrigeration coil and over the said drip pan, an air outlet from the header, a bafile set off from the said side wall, the said air outlet, bafile and side wall providing an air passage from the header over the top portion of the display case through the refrig- HOWARD O. JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,990,431 Frederick Feb. 5, 1935 2,066,013 Murphy Dec. 29, 1936 2,180,071 Smith Nov. 14, 1939 2,262,104 Lambrecht Nov. 11, 1941 2,332,174 Shreve Oct. 19, 1943 2,421,314 Brinkoeter May 27, 1947 OTHER REFERENCES Article in Ice and Refrigeration for July 1940, p. 12. 

